Dirty Greenhouse

The Two Thirsty Gardeners give us their top tips on how to clean a greenhouse, including the quickest (but ill-advised!) method and the best one – the safe and sensible method.

There aren’t many jobs that need doing in the garden over winter, and those that do are rarely much fun. Towards the top of this list of thankless tasks comes ‘clean the greenhouse’, a chore that runs the risk of getting you cold, wet and muddy for seemingly little reward. But unfortunately, it’s an important job, so wait for a dry, sunny day, fill a hot flask with coffee (or a hip flask with rum), turn on the radio and get scrubbing.

There are two main reasons why a clean greenhouse is a more productive greenhouse. Firstly, just as it’s a place where plants flourish, it can also be a home to thriving diseases. Many greenhouse plants are capable of picking up troublesome conditions; nasty diseases are able to settle down over the winter and rise again when new plants begin to grow, causing mildew, rot or worse to tomatoes, peppers and other inhabitants. Emptying out and scrubbing the inside of your greenhouse will help to make it a safer environment for growing.

The second reason to have gleaming greenhouse windows is that less dirt equals more light and warmth which, unfortunately, means you’re going to have to scrub the outside of the greenhouse as well.

Plant Pots from GreenhouseEmpty the greenhouse

Before any cleaning of the greenhouse begins, you need to remove as much as you possibly can from inside the greenhouse. Get rid of old plant matter (if it’s disease free, put it in the compost; otherwise a bonfire or your local council recycling centre is your best bet) and remove pots, shelves, canes and debris. If you’re recycling any of these items then put them in an orderly queue for their own scrubbing. If you’re using your greenhouse to overwinter plants then re-home them in a similarly warm environment for a few hours while you’re cleaning, and if there’s anything still growing that can’t be shifted temporarily cover it with waterproof material.

If you plant directly into the ground in the greenhouse it’s a good idea to refresh the soil at least every two years, so shovel out the top few inches ready to replace with fresh stuff when you’ve finished your cleaning duties.

Greenhouse after cleaningHow to clean a greenhouse

The easiest, quickest and most satisfying way to clean anything in the garden is to blast it with a jet washer. But aiming a high velocity stream of water at glass (or even greenhouses made of other materials) isn’t advisable – some jets are so powerful they can dislodge or even break panes – so if you’re determined to blast the algae free make sure any washers you use are designed for the structure you’re aiming them at.

The safest and most sensible option for cleaning a greenhouse is manual scrubbing with a cloth or sponge. If your panes are made of plastic then test-clean a small area first to make sure your chosen scrubber doesn’t scratch or damage the windows. The water you wash with will inevitably fall into the greenhouse soil, so harsh chemicals are to be avoided. There are some specialist greenhouse detergents available but Jeyes fluid is a decent choice. And if you encounter any stubborn bits of dirt – these usually lurk around the joins between frame and glass – use a flexible plastic scraper to prize them off.

Finally, as you clean, keep an eye out for greenhouse damage such as cracked pains or loose nuts and earmark them for a swift repair. After a bit of graft your greenhouse will have regained its sparkle and be ready to see some early growing action in spring.

Do you have any top tips on how to clean a greenhouse? If so let us know in the comments!


STIHL & Two Thirsty GardenersThe Two Thirsty Gardeners, Rich and Nick, are bloggers who love gardening, eating and drinking in equal measure! They love to share tales from their allotment including their experiments turning the spoils of their crops into alcohol, both the good and the bad!

To find out more about Rich and Nick, click here.

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